use symbolic constants for command widget preferences * QTerminal.cc: include new header file for shortcut preferences; (default_colors, color_names): removed obsolete methods; (notice_settings): replace preferences literals by symbolic constants; * QTerminal.h: remove obsolete methods, reorder enum CursorType matching the order in settings dialog * gui-preferences-all.h: add command window related preferences keys and default values as symbolic constants * gui-preferences-cs.h: add command window related preferences keys and default values as symbolic constants * gui-preferences-global.h: add global cursor blinking preferences constants * gui-preferences-sc.h: new header with shortcut related preferences * history-dock-widget.cc (notice_settings): replace font size literals by symbolic constants * file-editor-tab.cc (notice_settings): use cursor blinking pref. constants * main-window.cc (notice_settings): use cursor blinking pref. constants * module.mk: add new header gui-preferences-sc.h with shortcut preferences * resource-manager.cc (terminal_color_names, terminal_default_colors): remove obsolete methods * resource-manager.h: remove obsolete methods * settings-dialog.cc (settings_dialog, write_changed_settings): replace preferences key and default literals by new symbolic constants (read_terminal_colors, write_terminal_colors): use new arrays of symbolic constants and color names instead of literals * terminal-dock-widget.cc (terminal_dock_widget): use symbolic constants for font size preference key and default value * variable-editor.cc (variable_editor::notice_settings): use symbolic constants for font size preference key and default value